Various Noritake models have RS-232 interfaces built-in, so you would just need the 12v->5v part to run them if you used one of them.

Actually, almost ALL of them do.. but they're TTL interface.
In the end, the little board I'm making will be best suited for car, but can be used at home/office, too. It'll be about 2.5in x 2.5in big (guesstimate, right now), and have the RS-232 port for input. It'll take advantage of the +12V on from the Empeg sled (or you can plug it in)..
Of course, you can use anything you want, such as the all-in-one RS232-TTL cord someone posted about in this thread, as well.

Me.